Photochemical inactivation of viruses and bacteria in platelet concentrates by use of a novel psoralen and long-wavelength ultraviolet light

BACKGROUND: A photochemical treatment process has been developed for the inactivation of viruses and bacteria in platelet concentrates. This process is based on the photochemical reaction of a novel psoralen, S-59, with nucleic acids upon illumination with long-wavelength ultraviolet light (UVA, 320-400 nm). STUDY DESIGN AND METHODS: High levels of pathogens were added to single-donor platelet concentrates containing 3 to 5 x 10(11) platelets in 300 mL of 35-percent autologous plasma and 65-percent platelet additive solution. After treatment with S-59 (150 mu M) and UVA (0-3 J/cm(2)), the infectivity of each pathogen was measured with established biologic assays. In vitro platelet function after photochemical treatment was evaluated during 7 days of storage by using a panel of 14 assays. The in vivo recovery and life span of photochemically treated platelets were evaluated after 24 hours of storage in a primate transfusion model. RESULTS: The following levels of pathogen inactivation were achieved: >10(6.7) plaque-forming units (PFU) per mt of cell-free human immunodeficiency virus (HIV), >10(6.6) PFU per mL of cell-associated HIV, >10(6.8) infectious dose (ID50) per mL of duck hepatitis B virus (a model for hepatitis B virus), >10(6.5) PFU per mL of bovine viral diarrhea virus (a model for hepatitis C virus), >10(6.6) colony-forming units of Staphylococcus epidermidis, and >10(5.6) colony-forming units of Klebsiella pneumoniae. Expression of integrated HIV was inhibited by 0.1 mu M S-59 and 1 J per cm(2) of UVA. In vitro and in vivo platelet function were adequately maintained after antiviral and antibacterial treatment. CONCLUSION: Photochemical treatment of platelet concentrates offers the potential for reducing transfusion-related viral and bacterial diseases.